A Tale of Depression

Again this situation was simple last night.  The center is hard to find, even now.  Satellite Imagery shows a lot of rain on one side or the other.    So a wave makes sense , and with the storm now having sustained winds at 35mph.   Plenty of shear and central pressure has risen to 1007mb.   They are trying to make an omelet without the egg.

Meteorologist Larry Olson (Mike Scott)

activity_loop (4)

 

Tropical Depression Harvey Discussion Number 10
NWS National Hurricane Center Miami FL AL092017
500 PM EDT Sat Aug 19 2017

The cloud pattern of Harvey has continued to decay during the day,
at least in part due to 15-20 kt of northerly shear. The convective
area near the center is neither very concentrated or curved, and
overall the pattern more resembles that of an open wave than a
tropical cyclone. Based on the decay and data from the aircraft
mission this morning, the cyclone is downgraded to a tropical
depression. Another Air Force Reserve Hurricane Hunter aircraft
will investigate the system this evening to see if the circulation
still exists.

The intensity forecast is problematic. The current shear should
subside over the next 24 h, and the statistical guidance responds
to this by forecasting significant strengthening. On the other
hand, the structure of the cyclone has decayed to the point where
it may not be able to take advantage of the better environment, as
suggested by the ECMWF and GFS. The intensity forecast follows the
trend of the previous forecast, albeit with lower intensities, in
showing gradual strengthening until landfall in Belize or Yucatan.
However, an alternative forecast scenario is that the system
degenerates to an open wave and is unable to regenerate during the
next 72 h.

The initial motion remains 275/19. There is no change in the
forecast philosophy from the previous advisory, and there are only
minor tweaks to the forecast track. A low- to mid-level ridge
extending across the western Atlantic should keep Harvey, or its
remnants, on a fast westward course across the Caribbean Sea for the
next 36 h. Thereafter, there should be a weakness in the ridge north
of Harvey caused by a strong mid/upper-level low currently seen in
water vapor imagery over the Gulf of Mexico. This pattern should
cause a turn toward the west-northwest and a decrease in forward
speed. The track guidance remains in good agreement that Harvey
should pass near or just north of northeastern Honduras, and then
cross Belize and/or the Yucatan Peninsula into the Bay of Campeche.

A Tropical Storm Watch could be required for portions of the
northern coast of Honduras and northeastern Nicaragua tonight. At
the present time, there is enough uncertainty about whether Harvey
will actually be a tropical storm in 48 h that a watch is not
warranted.

FORECAST POSITIONS AND MAX WINDS

INIT 19/2100Z 14.1N 70.0W 30 KT 35 MPH
12H 20/0600Z 14.3N 73.0W 30 KT 35 MPH
24H 20/1800Z 14.6N 77.0W 35 KT 40 MPH
36H 21/0600Z 15.2N 80.5W 40 KT 45 MPH
48H 21/1800Z 16.0N 83.8W 45 KT 50 MPH
72H 22/1800Z 18.0N 89.0W 45 KT 50 MPH…INLAND
96H 23/1800Z 19.0N 92.0W 30 KT 35 MPH…OVER WATER
120H 24/1800Z 19.5N 94.0W 40 KT 45 MPH


 

TROPICAL DEPRESSION HARVEY FORECAST/ADVISORY NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092017
2100 UTC SAT AUG 19 2017

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE CENTRAL AND WESTERN CARIBBEAN SEA…NORTHERN
NICARAGUA…NORTHERN HONDURAS…BELIZE…AND THE YUCATAN PENINSULA
OF MEXICO SHOULD MONITOR THE PROGRESS OF HARVEY. WATCHES MAY BE
REQUIRED FOR PORTIONS OF THESE AREAS TONIGHT.

TROPICAL DEPRESSION CENTER LOCATED NEAR 14.1N 70.0W AT 19/2100Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST OR 275 DEGREES AT 19 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1007 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT…CENTER LOCATED NEAR 14.1N 70.0W AT 19/2100Z
AT 19/1800Z CENTER WAS LOCATED NEAR 14.0N 69.0W

FORECAST VALID 20/0600Z 14.3N 73.0W
MAX WIND 30 KT…GUSTS 40 KT.

FORECAST VALID 20/1800Z 14.6N 77.0W
MAX WIND 35 KT…GUSTS 45 KT.
34 KT… 60NE 0SE 0SW 60NW.

FORECAST VALID 21/0600Z 15.2N 80.5W
MAX WIND 40 KT…GUSTS 50 KT.
34 KT… 60NE 0SE 0SW 60NW.

FORECAST VALID 21/1800Z 16.0N 83.8W
MAX WIND 45 KT…GUSTS 55 KT.
34 KT… 70NE 0SE 0SW 70NW.

FORECAST VALID 22/1800Z 18.0N 89.0W…INLAND
MAX WIND 45 KT…GUSTS 55 KT.
34 KT… 90NE 30SE 40SW 60NW.

EXTENDED OUTLOOK. NOTE…ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 200 NM ON DAY 5…AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 23/1800Z 19.0N 92.0W…OVER WATER
MAX WIND 30 KT…GUSTS 40 KT.

OUTLOOK VALID 24/1800Z 19.5N 94.0W
MAX WIND 40 KT…GUSTS 50 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 14.1N 70.0W

NEXT ADVISORY AT 20/0300Z


GULFIR172311745

203938_5day_cone_no_line_and_wind

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s